replaced PVC box and still not fixed, lots of blowby.
#1
replaced PVC box and still not fixed, lots of blowby.
96 Volvo 850 non turbo, loosing oil out top of motor, blows up glove and smoking out dipstick even after oil trap box replacement, cleaning of ports on block and hoses leaving box to flame trap. Any ideas? Please help.
Last edited by bravrs1; 06-10-2014 at 09:58 PM. Reason: use correct part name
#5
#7
Which instructions did you use to do the PCV job? Did you hook up the tubes on the oil box properly?
A compression test would be easier than a leak down test. You will need a compressor to do a leak down.
http://www.youtube.com/watch?v=Z0hZELYgOX8
A compression test would be easier than a leak down test. You will need a compressor to do a leak down.
http://www.youtube.com/watch?v=Z0hZELYgOX8
Last edited by rspi; 06-11-2014 at 07:29 PM.
#8
Again, thanks for the help. The bottom port under the oil trap was completely plugged. I cleaned it out, dragging all the gunk to the outside of the block. I could put my finger in the hole and feel around, also put a low psi, probably around 20psi air into the hole and thought I could actually hear it moving around or splashing oil in the pan. How can I tell if the "oil passage" is clogged and how do I clean it?
#9
I sure hope so. The oil trap has two ports on the top. The one on the left-top (closest to the block) goes up to the valve cover. The one on the right-top is the hard tube that goes over to the flame trap (which has had the screen removed and is clean) at the throttle body.
Last edited by bravrs1; 06-12-2014 at 08:16 AM. Reason: to clarify
#10
#11
It is possible that it it could cause the oil on top of the engine. Worn rings is like having a plugged pcv, you wouldn't be under a vacuum your only have pressure. Do a compression test as most people are suggesting. But as I said before a cylinder leak down test is a better way to find out what's going on. If you have excessive leakage in one cylinder and put a glove over the oil filler and it fills with air then you know the rings are bad.
#12
The bottom port of the PCV black box goes all the way to the bottom of the oil pan and then hooks up. If you were pulling crud out of it it's very likely you didn't get it all.
The port in the block matches up with the port circled in the photo that is cast into the oil pan.
The bad news is if it's blocked you pretty much have to pull the pan to get in there to get it open.
The port in the block matches up with the port circled in the photo that is cast into the oil pan.
The bad news is if it's blocked you pretty much have to pull the pan to get in there to get it open.
Last edited by Kiss4aFrog; 06-19-2014 at 05:14 AM.
#13
The PCV crankcase vent hoses are plastic sheathed in rubber and can get brittle over time and break. Mechanics have also been known to break them during installation, particularly if they try to reuse the old ones. If that happens your PCV system will not operate correctly and you will still have crankcase pressure even if you replaced the oil trap and cleaned all the ports in the block.
Unfortunately, the only way to check this is to pull the whole system apart again, including removal of the intake manifold.
Unfortunately, the only way to check this is to pull the whole system apart again, including removal of the intake manifold.
#15
Or you can use an engine flush. Just make sure you read the label. Some are intended to be added just before an oil change and not to be driven on, others you can toss in and drive it until the normally scheduled LOF. I like the less aggressive one as there is less chance to plug the oil filter or oil pickup by trying to strip years of crud from the insides in 15 minutes
With Seafoam, I'd toss it in there and leave it in there. It's safe to drive with it in the crankcase and the longer it's in there the more chance it has of cleaning out the gunk.
For the first year of my cars life I replaced one quart of engine oil with transmission fluid. Trans fluid has more detergents in it. My engine was a short trip car and the crud from condensation and a bad PCV system was pretty thick. About the third or fourth LOF it was nice and clean inside the way it should be.
With Seafoam, I'd toss it in there and leave it in there. It's safe to drive with it in the crankcase and the longer it's in there the more chance it has of cleaning out the gunk.
For the first year of my cars life I replaced one quart of engine oil with transmission fluid. Trans fluid has more detergents in it. My engine was a short trip car and the crud from condensation and a bad PCV system was pretty thick. About the third or fourth LOF it was nice and clean inside the way it should be.
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